Fermi LAT Detection of a New Gamma-ray Source Associated with the Flat-Spectrum Radio Quasar S5 0532+82
ATel #12902; Stefano Ciprini (1. INFN Tor Vergata, Rome; 2. SSDC-ASI, Rome, Italy) Roberto Angioni (MPIfR-Bonn, Germany), Sara Buson (1. Univ. of Wuerzburg, Germany; 2. UMBC, USA), Simone Garrappa (DESY-Zeuthen, Germany) on behalf of the Fermi-LAT collaboration
on 2 Jul 2019; 08:04 UT
Credential Certification: Stefano Ciprini (stefano.ciprini@ssdc.asi.it)
Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar, Quasar
Referred to by ATel #: 16117
The Large Area Telescope (LAT), one of two instruments on the Fermi Gamma-ray Space Telescope, has observed increasing gamma-ray activity from a source positionally consistent with the flat-spectrum radio quasar S5 0532+82 (also known as 6C 0532+82, WN B0532.5+8236 and CRATES J0543+8238) with radio coordinates (J2000) R.A.: 85.911862 deg, Dec.: 82.641323 deg (Kovalev et al. 2007, AJ, 133, 1236) and with unknown redshift. This is a Very Long Baseline Array (VLBA) radio source, and is not in any published LAT catalog and was not detected in gamma rays by AGILE or EGRET.
Preliminary analysis indicates that S5 0532+82 was detected with high confidence on June 30, 2019 by the Fermi LAT with a daily averaged gamma-ray flux (E>100MeV) of (6.4+/-1.2) X 10^-7 photons cm^-2 s^-1 with a single power-law photon index of 2.0+/-0.1 (statistical uncertainty only). In particular S5 0532+82 was detected in the first six-hour interval of June 30 (00:00-06:00 UT) with a gamma-ray flux (E>100MeV) of (7.3+/-2.3) X 10^-7 photons cm^-2 s^-1 with a single power-law photon index of 1.8+/-0.2. S5 0532+82 is significantly detected by Fermi LAT also in the weekly interval from June 24 to July 30, 2019, while it is not reported in previous weeks.
This candidate gamma-ray blazar was detected by Fermi LAT in a time interval from 4.5 hours to 10.5 hours after the occurrence of the IceCube very-high-energy neutrino event IC-190629A of June 29 reported in GCN CIRCULAR #24910, and is located 6.5 degrees from the direction of IC-190629A.
Target of Opportunity observations with the Neil Gehrels Swift Observatory have been triggered. We strongly encourage further multifrequency observations of this object. Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. The Fermi-LAT contact persons for this source are S. Ciprini (stefano.ciprini at ssdc.asi.it) and R. Angioni (angioni at mpifr-bonn.mpg.de).
The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
